27 October 2026
Specifying aluminium sliding doors: six things to check before you order
Track count, wall thickness, drainage detail, glazing, hardware and threshold — the six variables that decide whether a sliding door performs on site.
A sliding door is easy to draw and hard to get right. The panels are heavy, the tracks collect water, and every compromise in the profile shows up as a draught, a rattle or a leak two winters later. These are the six points worth checking on any quotation.
1. How many tracks, and how wide the frame
Track count decides how the panels stack. A two-track frame lets two panels slide past each other; a three-track frame lets three panels gather into roughly one panel’s width, which is what you want when the opening has to be almost completely clear. The trade-off is frame depth: on the 40 × 65 door the two-track frame occupies 105 mm and the three-track frame 162 mm.
2. Wall thickness
Wall thickness is measured on the profile section, not on the outer face. A 2.0 mm wall and a 3.0 mm wall look identical from a metre away and behave differently under a 2.6 m high panel. Ask for the figure per profile, not per system.
3. Where the water goes
Every sliding door has drainage; the question is whether you can see it. Face-mounted spouts are easy to inspect and easy to block with a leaf. Hidden drainage looks cleaner and needs the internal channel to be kept clear. Either is fine, as long as the detail is on the drawing.
4. The glazing build-up, written out
“Double glazed” is not a specification. Ask for the build-up — for example 4 + 15A + 4 or 5 + 9A + 5 — including the glass supplier and whether the glass is original or processed elsewhere. The air space is doing most of the thermal work.
5. Hardware by name
Rollers and locks are the parts that wear. Named hardware sets can be replaced a decade later; unbranded ones often cannot. This also applies to the lock: a single-bar lock and a multi-point lock are not interchangeable on the same sash.
6. Threshold detail
A level track gives a flush floor and a better sight line; a high track gives a stronger water barrier. Decide which one you are buying before the builder sets the floor level, because it cannot be changed afterwards.
If you send an opening schedule, we will quote against these six points rather than a single “sliding door” line item.